Phase 2/3 open-label trial to assess the safety and tolerability of long-term treatment with lacosamide (SPM 927) in subjects with painful diabetic neuropathy. The safety and tolerability of the different doses of lacosamide will be investigated.

Number of Subjects With Adverse Events (AEs) Reported Spontaneously by the Subject or Observed by the Investigator. [ Time Frame: Throughout the study up to a maximum study period of 2.8 years ] [ Designated as safety issue: No ]

Number of subjects with adverse events (AEs) reported spontaneously by the subject or observed by the investigator (serious and non-serious).

Secondary Outcome Measures:

Change From Baseline in Average Daily Pain Score Using an 11-point Likert Scale (0-10). [ Time Frame: Baseline to end of entire treatment phase (maximum study period of 2.8 years). ] [ Designated as safety issue: No ]

Change from Baseline in average daily pain score using an 11-point Likert scale (0-10). On Likert scale, 0=no pain and 10=worst possible pain.

Change From Baseline in Average Pain Score as Measured by a 100mm Visual Analogue Scale (VAS). [ Time Frame: Baseline to end of entire treatment phase (maximum study period of 2.8 years). ] [ Designated as safety issue: No ]

Change from Baseline in average pain score as measured by a 100mm Visual Analogue Scale (VAS). On VAS 0mm=no pain and 100mm=worst possible pain.

Patient's Global Impression of Change (PGIC) from Baseline in Pain. Original categorical responses are much worse, moderately worse, mildly worst, no change, mildly better, moderately better, and much better. Reported results are presented as Better (sum of mildly, moderately, or much better), No Change, or Worse (sum of mildly, moderately, or much worse).

Change From Baseline in Average Pain Interference With Sleep (11-point Likert Scale) [ Time Frame: Baseline to end of entire treatment phase visit ] [ Designated as safety issue: No ]

Change from Baseline in average pain interference with sleep (11-point Likert scale) where 0=no interference with sleep and 10=worst possible interference with sleep.

Change From Baseline in Average Pain Interference With Activity (11-point Likert Scale) [ Time Frame: Baseline to end of entire treatment phase visit ] [ Designated as safety issue: No ]

Change from Baseline in average pain interference with activity (11-point Likert scale) where 0=no interfence with activity and 10=worst possible interference with activity.

Change From Baseline in Quality of Life Using the SF-36 Health Survey - Physical Component Summary (PCS) [ Time Frame: Baseline to Termination Visit ] [ Designated as safety issue: No ]

Change from Baseline in quality of life using the SF-36 Health Survey - Physical Component Summary (PCS). Values range from 0 to 100 with high values indicating a good condition. Positive change in baseline values indicate improvement in quality of life.

Change From Baseline in Quality of Life Using the SF-36 Health Survey - Mental Component Summary (MCS) [ Time Frame: Baseline to Termination Visit ] [ Designated as safety issue: No ]

Change from Baseline in quality of life using the SF-36 Health Survey - Mental Component Summary (MCS). Values range from 0 to 100 with high values indicating a good condition. Positive change in baseline values indicate improvement in quality of life.

This phase 2/3 open-label trial is being conducted at approximately 100 sites in the US to assess the safety and tolerability of long-term treatment with lacosamide (SPM 927) in subjects with painful diabetic neuropathy. Approximately 525 subjects will be enrolled. To qualify for this trial, subjects with symptoms of painful distal diabetic neuropathy ranging in duration from 6 months to 5 years must have completed trials SP665, SP742, or SP768 and, in the investigator's opinion, may benefit from long-term administration of lacosamide. Subjects will be titrated to their optimal dose of lacosamide (up to 600mg/day). The safety and tolerability of the different doses of lacosamide will be investigated throughout the trial. In addition, to determine what effect lacosamide has on diabetic neuropathic pain, subjects will use a diary to record their daily pain intensity and pain interference with sleep and activity. Subjects' quality of life will also be investigated.

Eligibility

Ages Eligible for Study:

32 Years to 81 Years

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Subjects who completed Study SP665, SP742, or SP768 and, in the investigators opinion, might benefit from long-term administration of SPM 927. Exception: subjects who prematurely discontinued Study SP742 or SP768 due to lack of efficacy or due to intolerability to trial medication may be eligible to participate in Study SP745, after consultation with the medical monitor.

Subject has aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) >=3 times the upper limit of the normal range (ULN) with total bilirubin >=2 times ULN or transaminases (AST and/or ALT) >=5 times ULN.

Subject has a clinically relevant medical condition that, in the opinion of the investigator, jeopardizes or compromises the subject's ability to participate in this trial.

Contacts and Locations

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Please refer to this study by its ClinicalTrials.gov identifier: NCT00235443